Re: [HACKERS] OR clause status

> > > I think the OID auto-casting should be very easy
> > > Once the development tree becomes unbroken...
> > Yes, I think there are some very good reasons to evaluate functions on
> > constants inside the parser.
>
> I wasn't actually suggesting making real changes to the parser. I
> _think_ I can get the OID vs int4 coersion problem fixed with a one-line
> change to a header file, but need a working tree to do it :(
>
> Any progress on getting the tree to compile? Are there some people who
> don't see a problem??
>
> > There are some operations that look at
> > index selectivity that need to know the constant value, rather than
> > knowing if the function returns an int. For example x > 3 looks at
> > the pg_statistics table to see max/min values.
> >
> > You certainly don't want to be evaluating functions on constants
> > inside the optimizer.
>
> ?? Why not? It is an optimization after all. I have never looked at the
> optimizer code however. Are you saying that the current optimizer
> doesn't have a pass or phase where functions could be evaluated? Should
> we add a pass to do this? I've been a bit worried about coding too many
> optimizations into the parser, since they might become pretty obscure
> buried in there.

The optimizer is much too complicated to be putting fmgr() function
calls in there. I know the parser is bad too, but I think it is best to
do it there. We already do some of it there anyway.

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